Range from the cheapest replacement of a toilet float valve £20 (Marian Plamada based in NW1) to the dearest replacement of a float valve £85 (LUCO - London Utility Company based in W1W).
Comparing plumbers estimates for replacing a toilet float valve in the cistern tank gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to replace a toilet float valve in W1U by posting a job with HaMuch and we will send it to plumbers in W1U.